3d printer interface lockout

ABSTRACT

A method for authenticating a user of a 3D printer to prevent unauthorized use of the 3D printer includes obtaining a user profile from a set of user profiles, each user profile corresponding to a user and including a stored multi-digit number; prompting the user, by a touch screen interface of the 3D printer, to input a personal identification number (PIN); preventing use of the 3D printer if the PIN does not match the stored multi-digit number; and authenticating the user if the PIN does match the stored multi-digit number. The method includes prompting the user to apply a force to the touch screen interface; detecting an applied force; comparing the applied force to a force threshold value; and preventing use of the 3D printer if the applied force is less than the force threshold value.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a divisional application of U.S. patentapplication Ser. No. 15/223,679, filed on Jul. 29, 2016, the content ofwhich is hereby incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to authenticating a user of a 3Dprinter, and more specifically, to preventing unauthorized use of a 3Dprinter.

BACKGROUND

3D printing, or additive manufacturing, is a process of making threedimensional solid objects based on blueprints provided by digital files.The synthesis of the desired 3D solid object is achieved bystrategically generating successive layers of an additive material in apattern on a platform of a 3D printer until the entire object iscreated. The synthesis of the 3D object is driven by the digital filesthat provide the specifications that describe how to create the patternof layers and the materials used to generate the object. The digitalfiles specifying the design are provided by the user, and examples ofthe digital files read by the 3D printer include G-code files,computer-aided design (“CAD”) files, STereoLithography (“STL”) CADfiles, and other file types generally used in additive manufacturingprocesses. In some instances, the digital files refer to a 3D model of anew object, but alternatively, the digital files can refer to a copy ofan object derived from the usage of a 3D scanner.

The generation of the successive layers of the additive material can beperformed, for example, according to any one of: (1) VatPhotopolymerisation, (2) Material Jetting, (3) Binder Jetting, (4)Direction Energy Deposition, (5) Powder Bed Fusion, (6) SheetLamination, or (7) Material Extrusion. Specific processes of MaterialExtrusion used to generate the successive layers can involve makingsequential deposits using fused deposition modeling (“FDM”), fusedfilament fabrication (“FFF”), or Direct Ink Writing (“DIW”).

The materials used as the “ink” of the 3D printer to generate the 3Dobject can include, for example, any of: powder material, polymermaterial, thermoplastics, eutectic metals, edible materials, rubbers,modeling clay, plasticine, metal clay, ceramic materials, metal alloys,papers, composite materials composed of ceramics and metallic materials(“cermet”), metal matrix composites, ceramic matrix composites,photopolymers, plaster, stainless steel, aluminum, plastic film, andmetal foil.

3D printers are generally protected from external influences by a buildcage, and, within the build cage, the 3-D printer typically includes thefollowing: (1) at least one extruder, (2) a guide rail system, (3) abuild platform, (4) at least one filament spool, (5) and at least onemotor for maneuvering the at least one extruder. In addition, theextruder can include a cooling system to regulate the temperature of theextruder.

Typically, during the operation of an FFF 3D printer, a plastic filamentis unwound from a filament spool and supplied to an extruder. Theextruder applies heat at a specific temperature to the filament, whichmelts the plastic filament to start material flow. Once the plasticfilament has begun to flow, the motor for maneuvering the extruder usesthe guide rail system to position (both horizontally and vertically) theextruder relative to the build platform to apply a first layer of the 3Dobject to the build platform. Due the characteristics of the filamentand the cooling system of the extruder, the filament cools shortly afterit has been extruded. Once the first layer has been applied, theextruder is repositioned, and a second layer is applied on the surfaceof the first layer. This process is repeated until the 3D object isfully constructed.

Some 3D printers include a touch screen interface, which allows users toeasily interact with the 3D printer. The touch screen interfacetypically includes a touch sensor panel, which may be a clear panel witha touch-sensitive surface, a display device that can be positionedbehind the panel so that the touch-sensitive surface substantiallycovers the viewable area of the display device, and a computer processorto interpret signals from the touch-sensitive surface. The touch screeninterface allow a user to provide various types of input to the 3Dprinter by touching the touch sensor panel using a finger, stylus, orother object at a location dictated by a user interface being displayedby a display device. This interaction can include, for example,inputting commands, adjusting settings, viewing information, etc.

In general, the touch screen interface can recognize a touch event(i.e., user interaction) and the position of the touch event on thetouch sensor panel, can then interpret the touch event in accordancewith the display appearing at the time of the touch event,and thereaftercan perform one or more actions based on the touch event.

SUMMARY

Example embodiments of the present invention provide methods and systemsto prevent unauthorized use of a 3D printer and to verify that an adultis operating the 3D printer.

3D printing requires precision during the printing process, since eachlayer must be precisely positioned relative to other, e.g., previouslyprinted, layers. Therefore, it is desirable to prevent a user frominterfering with the 3D printer during the printing process.Specifically, it is important that no external forces interfere with themotor, guiderail system, extruder, or the build platform as a 3Dobjected is printed.

Furthermore, it is advantageous to protect a user from dangerousconditions that occur during the printing process, since the operatingtemperature of the extruder can reach upwards of 397° F., which cancause serious injury to the user. Therefore, it is desirable for a 3Dprinter to prevent a user from inadvertently contacting the motor,guiderail system, extruder, or the build platform during the printingprocess.

Furthermore, operating a 3D printer requires adult supervision.Therefore, it is desirable for a 3D printer to have the capabilities toprevent an unsupervised child from operating the 3D printer. Inparticular, it is desirable for a 3D printer to be capable ofdifferentiating between a child user and an adult user.

According to an example embodiment of the present invention, a methodfor authenticating a user of a 3D printer to prevent unauthorized use ofthe 3D printer includes, responsive to user manipulation of a touchscreen interface for operating the 3D printer, obtaining a user profilefrom a set of user profiles, each user profile corresponding to arespective user and including a stored multi-digit number; prompting theuser, by the touch screen interface of the 3D printer, to input apersonal identification number (PIN); preventing use of the 3D printerif the PIN does not match the stored multi-digit number; and proceedingwith an authentication procedure for authenticating the user if the PINdoes match the stored multi-digit number.

In an example embodiment, the user profile includes at least one ofcontact information of the user and an answer to at least oneverification question. In an example embodiment, if the PIN does notmatch the stored multi-digit number, the method includes notifying theuser of the incorrectly input PIN, using the contact information; andupdating the user profile with an updated stored multi-digit number.Additionally, if the PIN matches the stored multi-digit number, in anexample embodiment, the method proceeds with the authenticationprocedure, which, in an example embodiment, includes prompting the userto input a response to the at least one verification question, where, ifthe response matches the stored answer to the at least one verificationquestion, the user is authenticated and a processor allows the user tooperate the 3D printer, but, if the response does not match the storedanswer to the at least one verification question, the method locks theuser out from using the 3D printer.

In an example embodiment, in the case of the lockout of the user fromusing the 3D printer due to entry of an incorrect answer to the securityquestion, the processor uses the stored contact information, e.g.,e-mail address, e.g., by transmitting an e-mail to the stored e-mailaddress, to notify the user that there has been an incident in which the3D printer was attempted to be used with entry of an incorrect answer tothe stored security question, that the previously stored PIN has beendisabled, and that a temporary PIN has been assigned (and stored in theuser profile). The user can then access an interface, e.g., via acomputer terminal, to modify the user profile, e.g., by setting a newPIN, setting a new security question, and/or setting a new answer to thesecurity question. In an example embodiment, in the case of the lockoutof the user from using the 3D printer due to entry of an incorrectanswer to the security question, the processor also displays on thetouch screen interface a message noting that the user has been lockedout from use of the 3D printer and/or that a new PIN has beenreassigned. In an example embodiment, that a new PIN has been reassignedis displayed on the touchscreen without display of the new PIN, so thatuser access to the new PIN is via the contact medium of the storedcontact information. The authentication procedure even following correctinput of the PIN is particularly advantageous because it can occur thata person with a relationship to the user to whom the PIN is assigned,e.g., a child, obtains access to the user's PIN, e.g., based on intimateknowledge of the user's life, characteristics, etc., but despite therelationship should not operate the printer due to safety reasons, e.g.,a minor child. The authentication procedure can function as a precautionto lockout such a person, e.g., the minor child, and provide the userwith an opportunity to reset the PIN to one unknown to the unauthorizedperson.

In an example embodiment, the method includes detecting, by the touchscreen interface, a force applied to the touch screen interface tooperate the 3D printer; comparing the applied force to a force thresholdvalue; and preventing use of the 3D printer if the applied force is lessthan the force threshold value. Furthermore, the method includesdetecting, by the touch screen interface, a number of inputs used toapply the applied force; preventing use of the 3D printer if the numberof inputs used to apply the applied force is greater than one, where therespectively applied forces of each of the individual inputs not meetingthe force threshold value; and authenticating the user as an adult if 1)the applied force is greater than or equal to the force threshold valueand 2) the number of inputs used to apply the applied force is equal toone. For example, the force threshold value corresponds to an averageforce that an adult user can apply using a single input. In anotherexample, the force threshold value corresponds to a value greater thanan average force that a child can apply using a single input. Theauthentication procedure is particularly advantageous because itprevents a child, for whom it is unsafe to operate the 3D printer, fromusing the 3D printer, for example, even if authenticating a particularuser is not required for using the 3D printer.

According to an example embodiment, the touch screen interface includesone or more pressure sensors (i.e., force sensors), configured to detecta force signal corresponding to an object exerting a force on thesurface of the touch screen. In this manner, the touch screen interfacecan determine whether the touch event is creating a large force or asmall force. For example, in an example embodiment, the touch screeninterface includes a plurality of force sensors arranged behind thetouch sensor panel, with each sensor providing an electric signal basedon the deflection of the touch sensor panel when a touch event occurs.

These and other features, aspects, and advantages of the presentinvention are described in the following detailed description inconnection with certain exemplary embodiments and in view of theaccompanying drawings, throughout which like characters represent likeparts. However, the detailed description and the appended drawingsdescribe and illustrate only particular example embodiments of theinvention and are therefore not to be considered limiting of its scope,for the invention may encompass other equally effective embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram corresponding to a method of generating a PINaccording to an example embodiment of the present invention.

FIG. 2 is a flowchart depicting a method of creating a user profileaccording to an example embodiment of the present invention.

FIG. 3 is a flowchart depicting a method of authenticating a useraccording to an example embodiment of the present invention.

FIG. 4 is a flowchart depicting a method of authenticating a useraccording to an example embodiment of the present invention.

DETAILED DESCRIPTION

FIG. 1 shows a PIN generation method 100 for generating a PIN using atouch screen interface 101 of a 3D printer. In an example embodiment,touch screen interface 101 operates under control of a processor and anon-transitory storage medium on which are stored program instructionsthat are executable by the processor, and that, when executed by theprocessor, cause the process to perform methods of operating the touchscreen interface 101, such as the example methods depicted in anddescribed below with respect to FIGS. 1-4.

In an example embodiment, touch screen interface 101 includes pressuresensors, which are configured to detect a force signal corresponding toa force exerted by an object on the surface of the touch screeninterface 101.

In an example embodiment, PIN Generation method 100 includes displaying,by touch screen interface 101, Home Screen 102, which includes, forexample, user selectable options 103, 104, 105, and 106. Options 103,104, 105, and 106 include, for example, a “Build” option, a “Filament”option, a “Level” option, and a “Tool” option. Option 106 can, forexample, correspond to the “Tool” option, in response to selection ofwhich touch screen interface 101 displays Tool Screen 107.

Tool Screen 107 includes, for example, user selectable options 108, 109,110, 111, 112, 113, 114, and 115. Options 108, 109, 110, 111, 112, 113,114, and 115 include, for example, a “Service” option, a “Wi-Fi” option,a “Calibrate” option, a “Jog Mode” option, a “Settings” option, a“Preheat” option, an “About” option, and a “Back” option. For example,option 112 can correspond to the “Settings” option, and option 115 cancorrespond to the “Back” option, in response to selection of which touchscreen interface 101 displays Home Screen 102. If a user selects“Settings” option 112, touch screen interface 101 displays SettingsScreen 116.

Settings Screen 116 includes, for example, user selectable options 117,118, 119, 115, and 120, where option 115 corresponds to “Back” option inresponse to selection of which Tool Screen 107 is displayed. Options117, 118, 119, and 120 can include, for example, a “Set Pin Code”option, a “Lock After Minutes” option, a “Renew Token” option, and a“Home” option. For example, option 117 can correspond to the “Set PinCode” option, and option 120 can correspond to the “Home” option, inresponse to selection of the latter of which touch screen interface 101displays Home Screen 102. In an example embodiment, if a user selects“Set Pin Code” option 117, touch screen interface 101 displays PinCreation Screen 121 via which a user can set a PIN to, going forward,require entry thereof for use of the 3D printer.

In an example embodiment, Pin Creation Screen 121 includes, for example,numeric keypad 122, which allows a user to generate PIN 123. PIN 123 canbe, for example, a multi-digit number. Alternative example embodimentssupport an alpha-numeric PIN. Pin Creation Screen 121 also includes, forexample, “Back” option 115 (for re-display of Settings Screen 116) and“Home” option 120 (for redisplay of Home Screen 102). Pin creationScreen 121 also includes, for example, “Enter” option 124, which allowsa user to set the theretofore entered number as the selected PIN 123. Inan example embodiment, once a user has entered PIN 123, touch screeninterface 101 displays, for example, Pin Verification Screen 125.

In an example embodiment, Pin Verification Screen 125 includes a numerickeypad 122, “Back” option 115 for redisplay of PIN Creation Screen 121,“Home” Option 120 for redisplay of Home Screen 102, and option 126,which is, for example, a “Done” option. Pin Verification Screen 125, forexample, prompts a user to, using numeric keypad 122, enter PIN 127 thathad previously been set in PIN Creation Screen 121. Once the user hasentered PIN 127 and selected “Done” option 126, touch screen interface101 verifies whether PIN 127 matches PIN 123 at step 128. If PIN 127matches PIN 123, touch screen interface 101 confirms that a user hasproperly entered PIN 123 and, for example, redisplays Home Screen 102,e.g., with a notification of success of setting the PIN. On the otherhand, if the compared PINs do not match, the method redisplays PINCreation Screen 121 to a new entry of PIN 123.

FIG. 2 is a flowchart that illustrates a method 200 for creating a UserProfile 204 using touch screen interface 101 of a 3D printer, accordingto an example embodiment of the present invention. Method 200 beings atstep 201.

At step 202, touch screen interface 101 prompts a user to inputinformation of User Profile 204, e.g., user's email address 205,multi-digit number 206, answer to a verification question 207, and otheruser credential information 207. For example, upon first use of theprinter, the touch screen interface 101 can prompt the creation of theprofile, including setting of access information by which to limitfuture use of the printer to a particular user. In an exampleembodiment, the system permits use of an administrator profile by whichto set multiple user profiles, each with respective access credentials.According to alternative example embodiments, one or more of theseinformational elements can be entered by separate input methods insteadof or in addition to by way of this illustrated flow. For example, amethod for generating a multi-digit number as a PIN has been describedwith respect to FIG. 1. In an example embodiment, a modified version ofthe method described with respect to FIG. 1 can be used for the flowdescribed with respect to FIG. 2, whereby screen 121 is a user profilegeneration screen, by which the PIN can be generated in addition toother user profile information. Other user credential information 207may include, for example, the user's telephone number, birthdate, etc.Once the user has entered all required information for the creation ofUser Profile 204, method 200 ends at step 203. In an alternative exampleembodiment, the PIN and/or other user profile information can be setremotely at a user terminal that is communicatively coupled to the 3Dprinter that includes its touch screen interface 101. For example, thecommunicatively coupled terminals are assigned to respective users whohave been given permission to use the 3D printer.

FIG. 3 is a flowchart for a user authentication method 300 using a touchscreen interface 101 of a 3D printer, according to an example embodimentof the present invention. The method beings at step 301.

At step 302, e.g., in response to a user input to begin operation of the3D printer, touch screen interface 101 obtains one or more UserProfile(s) 204. At step 303, touch screen interface 101 prompts a userto enter PIN 209. At step 304, authentication method 300 determines ifPIN 209 matches multi-digit number 206. If PIN 209 does not matchmulti-digit number 206, authentication method 300 proceeds to step 307.At step 307, authentication method 300 disables multi-digit number 206and notifies the user associated with User Profile 204, for example, byusing user email address 205. After multi-digit number 206 has beendisabled, authentication method 300 prompts the user to enter an updatedmulti-digit number with which the User Profile 204 had beenautomatically updated and which had been indicated in the notificationsent at step 307 or to enter an updated multi-digit number with whichUSER Profile 204 had been manually updated, e.g., in response to thenotification sent 307. For example, according to an example embodiment,the notification is an e-mail that includes a link in response toselection of which an interface is displayed, e.g., on a screen of aremote terminal, e.g., at which the e-mail is displayed, which interfaceincludes input fields for updating the multi-digit number 206 of UserProfile 204.

If PIN 209 matches multi-digit number 206, then authentication method300 proceeds to step 305 at which touch screen interface 101 prompts theuser to provide response 210 to one or more of the at least oneverification question. If response 210 does not match the stored answerto verification question 207, authentication method 300 proceeds to step307, which disables multi-digit number 206 and notifies the user of thedisablement.

If response 210 matches answer to verification question 207,authentication method 300 proceeds to step 308, which authenticates theuser as being permitted to operate the 3D printer. Method 300 ends atstep 308.

In an alternative example embodiment, if, at step 304, PIN 209 matchesmulti-digit number 206, authentication method 300 proceeds to step 308without asking the user to input response 210 to a verificationquestion.

FIG. 4 is a flowchart that illustrates a user authentication method 400for preventing use of a 3D printer by a minor, using touch screeninterface 101 of a 3D printer, according to an example embodiment of thepresent invention, which authentication method can be used incombination with requiring entry of a PIN code or even where operationof the 3D printer is not limited to only specifically identified personsby way of PIN or other identification methods. User authenticationmethod 400 begins at step 401.

At step 402, authentication method 400 prompts a user to apply pressureto touch screen interface 101. At step 403, authentication method 400detects applied force 404 applied by the user. Alternatively, instead ofa dedicated prompt for application of pressure and subsequent detectionof pressure applied in response to the prompt, pressure applied by auser when selecting an option, via touch screen interface 101,requesting operation of the 3D printer, is detected, the user-selectionof the option beginning the authentication method 400 with step 403.Next, at step 405, authentication method 400 determines if applied force404 is greater than or equal to force threshold value 406. For example,in an example embodiment, force threshold value 406 is set to a forcethat an average adult can exert on touch screen interface 101 with oneinput, e.g., with a press of a single finger. Therefore, if appliedforce 405 is less than force threshold value 406, authentication method400 determines that an adult is not applying pressure to the touchscreen interface 101, and authentication method 400 returns to step 401.

If applied force 405 is greater than or equal to force threshold value406, then authentication method 400 proceeds to step 407. At step 407,authentication method 400 determines if the user is using more than oneinput to apply applied force 404. If more than one input is used toapply applied force 404, then authentication method 400 determines thatthe user is not authenticated as an adult. In an example embodiment,where more than one pressure point is detected, the sensor detectswhether pressure at any single one of the pressure points meets thethreshold, in which case the user is authenticated but is otherwise notauthenticated. The authentication method then returns to step 401.

If force 404 is sensed as having been applied by a single input, e.g., asingle finger, then, at step 408, authentication method 400authenticates the user who has applied force 404 as an adult.Authentication method 400 ends at step 409.

In an example embodiment, the sensor for detecting the force includes acapacitor arrangement, where an external layer of the touch screeninterface 101 is flexible and can be bent downward towards an underlyinglayer, where the distance between the external and underlying layersvaries depending on the amount of pressure applied, which distance canbe detected based on a change in capacitance in response to a change indistance between electrodes integrated in the external and underlyinglayers, respectively. A plurality of electrode pairs can be arranged,e.g., in a grid, so that a pattern of distance values are detectable bywhich to ascertain the number of pressure points used to apply pressure.For example, a single pressure point is expected to match to a storedgradient of pressure over an applied area, e.g., with greatest pressureat the center of an applied pressure and gradually lower pressure in adirection that extends radially outward from the center. If a pressurepattern includes a center of greatest pressure, followed by graduallylower pressure, and then continuing further away from the initial centerwith a gradual increase in pressure to another center point of highpressure, such a pattern indicates presence of two pressure points.

In an example embodiment, the external layer of the touch screeninterface 101 can be formed of a glass or a flexible shape conformingpolymer.

An example embodiment of the present invention is directed to processingcircuitry, e.g., including one or more processors, which may beimplemented using any conventional processing circuit and device orcombination thereof, e.g., a Central Processing Unit (CPU) of a PersonalComputer (PC) or other workstation processor, to execute code provided,e.g., on a non-transitory computer-readable medium including anyconventional memory device, to perform any of the methods describedherein, alone or in combination. The one or more processors can beembodied in a server or user terminal or combination thereof. The userterminal can be embodied, for example, as a desktop, laptop, hand-helddevice, Personal Digital Assistant (PDA), television set-top Internetappliance, mobile telephone, smart phone, etc., or as a combination ofone or more thereof. The memory device can include any conventionalpermanent and/or temporary memory circuits or combination thereof, anon-exhaustive list of which includes Random Access Memory (RAM), ReadOnly Memory (ROM), Compact Disks (CD), Digital Versatile Disk (DVD), andmagnetic tape.

An example embodiment of the present invention is directed to one ormore non-transitory computer-readable media, e.g., as described above,on which are stored instructions that are executable by a processor andthat, when executed by the processor, perform the various methodsdescribed herein, each alone or in combination or sub-steps thereof inisolation or in other combinations.

An example embodiment of the present invention is directed to a method,e.g., of a hardware component or machine, of transmitting instructionsexecutable by a processor to perform the various methods describedherein, each alone or in combination or sub-steps thereof in isolationor in other combinations.

The above description is intended to be illustrative, and notrestrictive. Those skilled in the art can appreciate from the foregoingdescription that the present invention can be implemented in a varietyof forms, and that the various embodiments can be implemented alone orin combination. Therefore, while the embodiments of the presentinvention have been described in connection with particular examplesthereof, the true scope of the embodiments and/or methods of the presentinvention should not be so limited since other modifications will becomeapparent to the skilled practitioner upon a study of the drawings,specification, and following claims.

What is claimed is:
 1. A method for authenticating a user of a 3Dprinter to prevent unauthorized use of the 3D printer, the methodcomprising: obtaining, by processing circuitry, a user profilecorresponding to a user and including a stored multi-digit number;obtaining, via a touch screen interface of the 3D printer, input of apersonal identification number (PIN); comparing, by the processingcircuitry, the input PIN to the multi-digit number of the obtained userprofile; and executing, by the processing circuitry, an algorithmaccording to which use of the 3D printer is prevented if the PIN doesnot match the stored multi-digit number, and the user is authenticatedif the PIN does match the stored multi-digit number.
 2. The method ofclaim 1, wherein: the user profile further includes an answer to atleast one verification question; and the authentication of the user ifthe PIN matches the stored multi-digit number includes: prompting theuser to input a response to the at least one verification question; ifthe response matches the answer to the at least one verificationquestion, enabling the user to operate the 3D printer; and if theresponse does not match the answer to the at least one verificationquestion, preventing use of the 3D printer.
 3. The method of claim 2,wherein the user profile further includes user contact information, and,if the response does not match the answer to the at least oneverification question, the algorithm causes the processing circuitry todisable the PIN and transmit a communication using the contactinformation of the user profile informing of the disablement of the PIN.4. The method of claim 3, wherein, if the response does not match theanswer to the at least one verification question, the algorithm causesthe processing circuitry to generate a new PIN and include anidentification of the new PIN in the transmitted communication.
 5. Themethod of claim 3, wherein, if the response does not match the answer tothe at least one verification question, the algorithm causes theprocessing circuitry to include in the transmitted communication a linkto an electronic location via which a new PIN and multi-digit number aresettable.
 6. The method of claim 5, wherein the electronic location is awebpage, settings set at the webpage being updated in a central servercommunicatively coupled to the 3D printer.
 7. A non-transitory,machine-readable storage medium on which are stored program instructionsthat are executable by a processor and that, when executed by theprocessor, cause the processor to perform a method for authenticating auser of a 3D printer to prevent unauthorized use of the 3D printer, themethod comprising: obtaining a user profile corresponding to a user andincluding a stored multi-digit number; obtaining, via a touch screeninterface of the 3D printer, input of a personal identification number(PIN); comparing the input PIN to the multi-digit number of the obtaineduser profile; and executing an algorithm according to which use of the3D printer is prevented if the PIN does not match the stored multi-digitnumber, and the user is authenticated if the PIN does match the storedmulti-digit number.
 8. The machine-readable storage medium of claim 7,wherein: the user profile further includes an answer to at least oneverification question; and the authentication of the user if the PINmatches the stored multi-digit number includes: prompting the user toinput a response to the at least one verification question; if theresponse matches the answer to the at least one verification question,enabling the user to operate the 3D printer; and if the response doesnot match the answer to the at least one verification question,preventing use of the 3D printer.
 9. The machine-readable storage mediumof claim 8, wherein the user profile further includes user contactinformation, and, if the response does not match the answer to the atleast one verification question, the algorithm causes the processingcircuitry to disable the PIN and transmit a communication using thecontact information of the user profile informing of the disablement ofthe PIN.
 10. The machine-readable storage medium of claim 9, wherein, ifthe response does not match the answer to the at least one verificationquestion, the algorithm causes the processing circuitry to generate anew PIN and include an identification of the new PIN in the transmittedcommunication.
 11. The machine-readable storage medium of claim 9wherein, if the response does not match the answer to the at least oneverification question, the algorithm causes the processing circuitry toinclude in the transmitted communication a link to an electroniclocation via which a new PIN and multi-digit number are settable. 12.The machine-readable storage medium of claim 11, wherein the electroniclocation is a webpage, settings set at the webpage being updated in acentral server communicatively coupled to the 3D printer.